Setting initial timing L76

[Philip A.]

L76 spec is 10 degrees BTDC at 750 rpm w/o VAC. I have read posts from the archives regarding the challenges of setting initial timing since idle is rough (unstable) at 750 rpm and mechanical advance can start at 700 rpm. My question is would it be possible to safety wire closed the mechanical advance and set the initial timing at a higher smoother (stable) idle setting; and then after remove the safety wire and adjust idle back down? Would this cause some other problem?

[Edward J.]

Re: Setting initial timing L76

L76 spec is 10 degrees BTDC at 750 rpm w/o VAC. I have read posts from the archives regarding the challenges of setting initial timing since idle is rough (unstable) at 750 rpm and mechanical advance can start at 700 rpm. My question is would it be possible to safety wire closed the mechanical advance and set the initial timing at a higher smoother (stable) idle setting; and then after remove the safety wire and adjust idle back down? Would this cause some other problem?

Philip that should work fine. it makes for a more precise setting, it just takes a little extra time. I would also set the dwell first,And put the fast idle cam on the first step and see if that is around the 900 RPM mark.

[Frank D.]

Re: Setting initial timing L76

You can rubber band the centrifugal weights and not have wire whirling around in your distributor....but I've never had to do it....

[Larry M.]

Re: Setting initial timing L76

Yes you can lock in the weights and then set the initial advance at a higher engine speed. However, I generally just run the engine up to around 3500-4000 RPM and set the total mechanical advance at around 38 degrees. Vac can is disabled and vacuum line plugged. You need a dial back timing light to do this or measure and mark the harmonic damper.

Make certain that mechanical advance is all in at the 3500-4000 RPM...........it should be............but verify that no additional advance is occurring.

Engine is not that sensitive to initial advance, but is very sensitive to total mechanical advance. Especially at WOT (wide open throttle). So that is what we aim to control.

Larry

[Duke W.]

Re: Setting initial timing L76

The OE 365/375 HP engine's centrifugal curve is all in at 2350 (24 deg.), but you should verify this with a timing light. Assuming the curve is OE set total WOT advance (VAC disconnected, hose plugged) with a dial back timing light as high in the 36-40 range as the engine will tolerate without detonation.

Since the OE full centrifugal comes in so early you can do this somewhere between 2500 and 3000 assuming the centrifugal is OE, but make no assumptions, verify first!

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Duke